China, explained.
The militarisation of subsea infrastructure is a prominent reflection of geopolitical uncertainty (Yuichiro Chino/Getty Images)
China’s deep-sea cable cutter isn’t about technology but theatre, less a weapon and more an effort to generate unease.
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Cutting through the narrative: What China’s deep-sea cable-cutter really signalsCutting through the narrative: What China’s deep-sea cable-cutter really signals
A weekend headline from the South China Morning Post declaring “China unveils a powerful deep-sea cable-cutter that could reset the world order” caught plenty of attention and amplified anxieties about undersea infrastructure vulnerability and geopolitical competition. The SCMP described China’s new cable-cutting device as capable of severing heavily fortified submarine cables at depths of up to 4,000 metres, twice the operational depth of most existing subsea communications infrastructure.
Yet this headline, despite its dramatic claims, does not fully align with the technical realities of undersea cable infrastructure. The International Cable Protection Committee, a non-profit organisation representing more than 230 members that collectively represent over 98% of global submarine telecommunications cable infrastructure, advises that cables at such depths are neither armoured nor particularly fortified.
At extreme depths, submarine cables are lightweight and thin, typically only 17 to 21 millimetres in diameter, resembling a garden hose. In rare cases, armoured cables may be used where the undersea terrain is known to be particularly rugged, but this introduces additional challenges. Armoured cables are difficult to bend and bringing them to the surface for repairs is complicated and costly.
Generally, deep-sea cables rely on the seabed’s remote depth for their security as the deep sea lies well beyond the reach of anchors or fishing – activities typically responsible for cable damage. Armouring and protective measures are standard practices only in shallower waters, typically under 1,500 metres, where physical threats are tangible. Furthermore, as I learnt during my doctoral fieldwork, industry experts caution that at extreme depths, armoured cables risk snapping under their own weight, rendering such protective measures not only unnecessary but counterproductive.
If armoured cables at such depths are not the norm – and they are not – what precisely is China’s new device intended to overcome?
China revealed that it has developed a compact deep-sea cable-cutting device that is powerful enough to severe communication lines, the South China Morning Post reported. https://t.co/baeEzIKpxO
— Bloomberg (@business) March 22, 2025
The discrepancy between China’s new stated capability and the material reality of subsea infrastructure raises critical questions about Beijing’s motivations behind the disclosure. The very public unveiling of such a device indicates that China’s intent is less technological innovation and more strategic communication.
The concept of strategic narratives, as described by international relations scholars, offers valuable context here. Strategically formulated and projected messaging helps states shape global perceptions about their roles, capabilities, and intentions within the international order. By revealing this new tool through a carefully orchestrated media discourse, first detailed in a peer-reviewed Chinese journal and then amplified internationally by the SCMP, Beijing is potentially seeking to assert its deterrence capabilities, projecting power and maritime reach without actual conflict. Domestically, it feeds into a nationalist rhetoric of how China can independently develop advanced, world-leading technology without relying on external actors.
By showcasing its ability to disrupt global communications, Beijing, at home, can project itself as powerful enough to influence global security dynamics while countries in Europe, in concert with NATO, scramble to protect their critical underwater infrastructure.
Without proper scrutiny, sensational claims easily proliferate, shaping public and policymakers’ perceptions.
This portrayal of China’s underwater technological ascendancy arrives at a moment when the international order itself is increasingly in flux. With the United States adopting an “America First” posture, traditional alliances and security assurances appear less certain. Consequently, US allies – including middle powers like Australia – find themselves reconsidering how best to recalibrate security policies, navigating both tangible threats and externally amplified threat perceptions designed to induce strategic unease.
The militarisation of subsea infrastructure is a prominent reflection of this uncertainty. Incidents, such as the sabotage of the Nord Stream pipelines and several cases of accidental damage to cables in the Baltic, have amplified concerns over seabed security, prompting NATO and other organisations to establish dedicated seabed security-focused initiatives. The SCMP announcement exploits these existing anxieties – designed less to inflict immediate physical harm than to influence perceptions, shape decisions, and subtly deter geopolitical rivals.
There is also a less obvious yet critical economic dimension to China’s messaging around its advanced “cable-cutter” capability. The global submarine cable market is dominated by four companies: Alcatel Submarine Networks (France), SubCom (USA), NEC (Japan), and China’s HMN Tech. If Western governments and their allies, alarmed by the perceived Chinese threat, impose stringent new regulations mandating unnecessary armouring along entire cable routes – including deep-sea sections – it would drastically escalate manufacturing costs and operational complexity. Such an overreaction would primarily operationally burden Western cable companies and Japan, potentially slowing deployment rates, increasing capital expenditure, and inadvertently benefiting China’s cable industry.
The rapid amplification of the original SCMP story across global media platforms further illustrates the power of strategic communication. Without proper scrutiny, sensational claims easily proliferate, shaping public and policymakers’ perceptions. Media outlets, often unfamiliar with the technical specifications of undersea cable infrastructure, risk becoming unwitting accomplices – translating deceptive state signalling into geopolitical anxiety.
As the international order continues to shift, middle powers cannot afford to respond emotionally to displays of technological capability whose purpose may rely more on geopolitical manoeuvring than operational necessity. For nations such as Australia, where 99 per cent of international data transfer depends on submarine cables, navigating these narratives wisely is critical. Rational, informed assessments – not sensationalised accounts – should underpin decisions about infrastructure protection. Canberra and its regional partners should focus on enhancing genuine resilience: developing cable redundancy, investing in rapid repair capabilities, and bolstering international coordination.
Policymakers would, therefore, do well to recognise that in an era of intensified maritime infrastructure competition, power resides not only in technological capability but also in the effectiveness of one’s discursive persuasiveness. China’s deep-sea cable-cutter isn’t about the technology – it’s theatre. It’s less a weapon and more a signal crafted to unsettle rather than destroy. China, as a great power in its own right, understands that external perceptions can sometimes bolster state power both at home and abroad. If the SCMP story reveals anything, it is that Beijing has mastered both the tool and the tale – and understands that sometimes the tale can cut deeper.
About the author
Cynthia Mehboob
Cynthia Mehboob is a PhD Scholar based at the Department of International Relations at the Australian National University.
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